1. Field of the Invention
This invention relates to microwave reflector antennas. More particularly, the invention relates to a Radio Frequency (RF) seal for the joint between the feed and main reflector/antenna base of a reflector antenna.
2. Description of Related Art
Self supported feed assemblies typically include a subreflector supported proximate a focal point of the main reflector by a feed waveguide coupled to a mounting hub fastened to an antenna base that also supports the main reflector. A joint between the main reflector/antenna base and the mounting hub creates an RF leakage path to the rear of the reflector antenna that generates signal backlobes known to degrade the reflector antenna signal pattern. A vertex plate is commonly applied to the proximal end of the feed waveguide and/or mounting hub to improve the overall return loss of the antenna.
Prior reflector antennas typically apply a plurality of conductive seal(s), such as a spring ring(s) and/or conductive grease, to seal the joint and/or area between the vertex plate and the main reflector/antenna base. Conductive grease application is time-consuming and may be difficult for installation personnel to correctly apply in exposed reflector antenna mounting environments, such as high atop radio towers. Also, conductive grease application may require skin protection for the installation personnel, further complicating application.
Competition in the reflector antenna market has focused attention on improving electrical performance and minimization of overall manufacturing, inventory, distribution, installation and maintenance costs. Therefore, it is an object of the invention to provide a reflector antenna feed assembly mounting hub joint seal that overcomes deficiencies in the prior art.